Method of cooling internal combustion engine and cylinder head for same



E. e. FAHLMAN METHOD OF COOLING INTERNAL COMBUSTION ENGINE AND CYLINDERHEAD FOR SAME 2 Sheets-Sheet 1 Filed Jan. 22, 1938 Everett G. FahlmanATTORNEYS Jan. 30, 1940. E. G. FAHLMAN METHOD OF COOLING INTERNALCOMBUSTION ENGINE AND CYLINDER HEAD FOR SAME Filed Jan. 22, 1938 2Sheets-Sheet 2 INVENTOR Everett G.Fahlman BY ATTORNEYS Patented Jan. 30,1940 UNITED STATES giant rarer tries METHOD OF COOLING INTERNAL COMBUSTION ENGINE SAME ANDv CYLINDER HEAD FOR Everett G. Fahlman, Rocky River,Ohio, assignor to The Permold Company, Cleveiand, Ohio, a

corporation of Ohio Application January 22, 1938, Serial No. 186,387

8 Claims.

for cooling internal combustion engines and more particularly toimproved cylinder heads for such engines.

It is an object of the invention to provide a cylinde'r head for anengine having a cooling sys-.

tem employing forced circulation, which effectivez'y maintains asubstantially uniform temperature around the combustion chambers and 10'in which overheating in one portion and exeessive cooling in anotherportion of the head is avoided.

Another object is to provide a cylinder head having a chamber for thecirculation therei through of a coolant in communication with a flowsfrom inlets to an outlet or outlets and a which chamber has at spacedintervals a plurality of passageways extending across the cylinder headthrough which the cooling liquid flows and which vare proportioned incross-sectional area to direct the cooling liquid to flow over I theportions of the combustion chamber wall 40 liquid chamber for the flowofcooling liquid through the head.

A further object is to provide a cylinder head for an internalcombustion engine which is simple in designand construction andinexpensive to' manufacture. Other objects and advantages will becomeapparent from the following detailed description of the invention.

In the" usual construction of present-day internal combustion engines ofthe type employed in automotive vehicles, a' number of cylinders arearrangedin parallel relation and one behind another. Each cylinderreceives a reciprocable piston and all of the pistons are arranged toacmate a common crankshaft. The cylinders are formed in an engine blockhaving one or more (Cl. 123-473) invention relates to a method and meansI cooling liquid jackets which surround the cylinders. A cylinder headis secured to the engine block and arranged to overlie one end of eachof the cylinders to provide combustion chambers. A cooling liquidchamber is formed in the cylinder head and a number of passages aiiordcommunication between the cooling liquid jacket around the cylinders andthe cooling liquid chamber inthe cylinder head. The cooling liquid iscirculated through the cylinder jacket, cylinder head chamber and thenthrough a radiator which dissipates or withdraws from the cooling liquidthe heat gained in passage through the engine block and cylinder head.This circulation preferably accomplished by means 'of a pump which. isusually positioned in the circulatory system between the cylinder headand radiator or between the radiator and cylinder jacket.- 7 because ofa positive pressure above that of the atmosphere exerted on the coolingliquid in the cylinder jacket and cylinder head.

According to the present invention the cooling liquid passages extendingbetween the chamber in the cylinder head and the water jacket in theengine block are positioned and proportioned with respect to one anotherto present different degrees of frictional resistance to the flow there-.through of the cooling liquid from the engine block into the cylinderhead. For those passageways which are remote from the part of the engineblock in which fresh cooling liquid from the radiator is firstintroduced, it is desirable to have a reduced frictional resistance tothe flow of coolingliquid, while for those passages relatively close tothe fresh cooling liquid inlet of the engine block it is preferred tohave a rela tively high frictional resistance to the flow of liquid.Such a system tends to equalize the relative heat absorbing capacitiesoithe several portions of cooiing liquid which flows into the cylinderhead cooling chamber through the various passages. After beingintroduced into the chamber of the cylinder head the cooling liquidflows at a relatively high velocity over all portions of the bottom walland in a general direction toward the cylinder head cooling liquidoutlet. By pro- The latter position is to be preferred viding a coursefor the iiow of cooling liquid as rapidly as it is formed.

A proportional relationship is observed, as

- closely as possible considering the requirements of commercialmanufacture, between the amount of water flowing through the cylinderhead at one of the restricted area stages and the total cross-sectionalarea of such stage as well as a relationship between the cross-sectionalarea of the various stages and the cross-sectional area of the coolingliquid outlet from the cylinder head.

In the drawings, a cylinder head is shown which embodies the principlesof thisinvention. Certain features of the cylinder head form the subjectmatter of my co-pending application Serial No. 185,881, filed January20, 1938.

Figure 1 is a plan view partly in section and with parts removed of acylinder head secured to a four-cylinder engine block;

Fig. 2 is a side elevational view partly in section and with partsremoved of the cylinder head and engine block illustrated in Fig. 1;

Fig. 3 is a bottom view of the cylinder head shown in Figs. 1 and 2;

Figs. 4, 5, 6, and '7 are detail sectional views taken substantially onthe lines 4-4, 5-5, 66, and 1-1, respectively, of Fig. 1 and enlargedwith respect thereto.

Referring to the drawings by numerals of reference which are applied tolike parts throughout the several figures, the cylinder head comprises abottom or compression wall I which overlies a plurality of cylinders 2formed in an engine block 3 and arranged in line with one another withtheir axes substantially parallel. Over each of the cylinders 2 thebottom wall I is formed into a dome i which provides a combustionchamber 5. An upper wall 6 is disposed over the compression wall I ofthe cylinder head and in spaced relation with respect thereto to providea cooling liquid chamber 1. This cooling liquid chamber is continuousover substantially the entire area of the bottom compression wall I andoverlies all of the domes 4 of the combustion chambers; The peripheralmarginal portions of the upper wall 6 are curved into lateral walls 8which join with the bottom compression wall I to enclose the coolingliquid chamher I. A plurality of posts 9 extend through the coolingliquid chamber l and are integrally formed with the bottom wall I andtop wall 6 of the cylinder head. These posts have longitudinal centralapertures which receive stud bolts ill for securing the cylinder head tothe engine block. At each end of the cylinder head a pair of posts I!are formed into the lateral walls 8 of the cylinder head and are alsoaxially apertured to receive holding bolts. Additional stud bolts andnuts are secured in bosses I2 formed on a portion of the bottom orcompression wall I of the cylinder head over which there is no coolingliquid chamber. Between the posts 9 and II extend reinforcing ribs I4.

The cooling liquid chamber I formed in the cylinder head communicateswith a cooling liquid jacket or chamber l5 formed in the engineblockthrough a plurality of cooling liquid passages, indicated bythealphabetical letters A, B, C, D, E, F, G, H, J, K, L, M, N, P, R, Sand T, shown in Fig. 3 of the drawings. Between the cylinder head andengine block is a gasket I6 which affords a fluid-tight connectionbetween the two and prevents loss of compression and escape or" coolingliquid.

Fresh cooling liquid is introduced into the cooling liquid jacket 55 ofthe engine block -through inlet I1 and is forced through the engine bymeans of a pump I8 whichmay be driven by the engine in any well knownmanner. The cooling liquid inlet passages A, B and c, seen at the leftof Fig. 3, are a relatively great distance away. from the inlet H and asuitable circulating pump, I 5 of conventional design, which may besecured to the engine block 3 at the inlet II. The pump itself is notshown in the drawings, but the hous ing therefor is indicated at I8.Accordingly, the

cooling liquid flowing into the cylinder head 10..

chamber I through these passages must first, travel substantially theentire length of the engine block 3 through the cooling liquid jacketI5. Conversely, the cooling liquid inlets R, S and T, seen at the rightof Fig. 3, are relatively close '15 to the inlet I! and pump I8, beinglocatedin the cylinder head at the forward end of the' engine andcommunicating with the block jacket I5 directly above the inlet H.

In flowing through the jacket I5 forsubstan 20 tially the entire lengthof the engine block the cooling liquid, entering the cooling liquid chamher I of the cylinder head through thecooling' liquid passages A, B andC, loses considerable pressure because of the retarding or frictional 25efiect of the walls of the cooling liquid jacketlfi, The correspondingpressure losses on the cooling liquid entering the cooling chamber 1through the inlet passages R, S, and T is relativelysmall since thiscooling liquid flows substantially di- 30' rectly from the inlet I?through the passages R, S, and T. For this reason it is desirablethatthe frictional resistance to the flow of 1 cooling f liquid into thechamber 1 from the jacket I5 Y be considerably less through the passagesA, B, and C than through the passages R, S, and T, so that the quantityof liquid flowing through the latter passages in a unit length of timeduring normal operation of the engine will not be greatly in excess .ofthat flowing through the 0 former passages and preferably less inamount, as will presently appear.

Another factor which is to be considered in determining the relativesizes of the cooling liq-y uid passages is the temperature of thecooling 5 the portions of the engine block 3 which form the coolingliquid jacket :5. Of course, during normal operation of the engine witha force pump I8 the water circulates through the jacket ill withsufficient rapidity so that a substantial temperature difierential ismaintained between the metal of the jacket and the cooling liquid.However, other factors being the same, that cooling liquid entering thecylinder head chamber 1 through the inlet passages A, B, and C has agreater opportunity to become elevated in temperature than the coolingliquid entering through the passages R, S, and T. Accordingly, thepassages A, B, and C are substantially larger in cross-sectional areathan the passages R, S, and T, so that the latter offers the greaterresistance to the flow of cooling liquid from the jacketI5. In thismanner the flow through passages R, S, and T is retarded to increase therelative period of time that cooling liquid entering the head chamber 1through these passages remains in the 7 block jacket I5 to absorb heat,thus tending to equalize the temperatures and heat absorbingcapacitiesof the coolingliquid entering the'chamberlat opposite ends ofthe cylinder head. Another effect of increasing the flow resistance ofthepassages R, S, and T is that the cooling liquid, under the pressureof pump ill seeks other outlets from the jacket 55 and flows through thejacket and out the passages more remote from the inlet, such as the.passages A, B, and C. Proportionately as the cross-sectional area of thead jacent passages is decreased, the quantity of cooling liquid divertedfrom these passages tov flow through more remote passages is increased.

- The tendency for cooling liquid flowing in a general longitudinaldirection through the engine block to become elevated in temperaturei's'increased in engines of the V-type.

In such cases, engines of the V-type can be made to show greatlyimproved performance throughuse of the presentinvention, which aims tosupply cooling liquid in sufficient quantity and at a suitabletemperature to the several domes 4 of the compression wall I of thecylinder head so that substantially equal cooling capacity is suppliedto each of the combustion chambers of the engine and the operatingtemperature of all the cylinders remains substantially uniform. In thecylinder head illustrated, the cooling liquid inlet passages into thecylinder head are in the formof round or cylindrical holes. By adding upthe individual cross-sectional areas of all the passages, the totalavailable cooling liquid inlet passage area is obtained. In'thefollowing table the relative sizes of the various passages aresubstantially indicated by expressing its area in percentage of thetotal area of the cooling liquid inlet passages between the jacket !5and head-chamber 1.

From the above table it appears that about 37 of the-total passage areais furnished by the three remote inlets A, B and C, while only about 10%is furnished by the inlets R, S and T,

which are adjacent the jacket inlet H; The arrangement as to locationand size of the cooling liquid passages issuch with respect to thecooling liquid inlet into thecylinder jacket and the coolving liquidoutlet from the cylinder head, that the flow of cooling liquid into andthrough the cylinder head is controlled to maintain uniform temperature.Substantially any performance of the cooling system that is desired maybe obtained by variation of the design described in accordance with theprinciples of the invention. The.

sizes of the various cooling liquid inlets into the cylinder head areproportioned or adjusted with respectto one another so that thequantities of cooling liquid admitted to various portionsof the thecylinder head, with respect to the various cylinders or combustionchambers, atsubstantially uniform temperatures. The adjustment-or theproportioningof cooling liquid inlet size may be'eifecte'd by coring theholes to proper dimensions when the cylinder head is cast, or bydrillcylinder head. chamber have cooling capacities" suificient tomaintain all analogous portions ofing the holes to the desired size.Another method is to make the holes through the head and engine blocklarger than required'and to vary the size f the openings in the gasketlfi'in order to give the desired cross sectional area to the passages.In thus adjusting the flow by regulation of inlet size, considerationmust be given to the location of the cooling liquid circulating pump aswill be later explained and the heating of the cooling liquid as itpasses through the jacket l5. For a bank of cylinders as shown in thedrawings, with the cooling liquid inlet into the jacket 15 at one end ofthe latter a satisfactory proportioning ofv the inlets into the cylinderhead chamber has been found to be one wherein the available passagewayarea for the flow of cooling liquid into the cylinder head chamber '5furnishedby the remote inlets A, B, and C is nearly four times as greatas that furnished by the adjacent inlets R, S, and T. The inlet passagesbetween the adjacent passages and the remote passages vary in sizesubstantially in accordance with their distance from the jacket inlet H.For example, the intermediate remote passages D, E, F, and G have acombined cross-sectional area of about 22% of the total available inletpassage area. The intermediate adjacent passages L, M, N, and

T have a combined. cross-sectional area of about 14% of the totalcooling liquid inlet passage area. Thus the seven remote passages, A'through G,

have a combined cross-sectional area of about 59% of the total inletarea while the seven" adjacent passages, L through '1, have a combinedcross-sectional area of only about 24% of the total inlet area, which isabout 40% of the area of the remote passages. The remaining 17% of thetotal passage area is furnished by the central passages H, J and Kpositioned in the central portion of the cylinder head substantially onthe median line thereof.

In carrying out the present invention in connection with various designsof internalcombustion engines the proportion between the crosssectionalarea of the combined cooling liquid passages remote from the enginejacket inlet with respect to the combined. area of the passages ad--jacent the inlet, is subject to considerable variation. A number offactors are to be considered in determining therelative proportionbetween the cross-sectional area of the remote'and the adjacentpassages. One such factor is the design and location of the force pumpHi. If the pump is located at one end of the engine block, as shown inthe drawings, a greater difference in crosssectional area between theremote and adjacent passages is desirable than in the case where thepump is located so that the inlet I! com'muni cat-es with the jacket l5midway between the ends of the engine block. Another factor is theresistance to the flow of cooling liquid offered by the jacket It. Ifthis jacket hasrelatively wide and open passageways the cooling liquidflows with considerable ease, whereas if the passageways are'thin andnarrow so that only restricted openings are present then the resistanceto the flow of cooling liquid is increased and'it is desirable that aproportionatelyv larger difference be provided in the cross-sectionalareas of the remote passages into the chamber 1 with respect to thepassages which are adjacent the inlet H. For an arrangement such as thatillustrated in the drawings it has been found that a proportion ofcooling liquid passage areas into the chamber 1 such that the combinedcrosssectional areas of the adjacent passages is from 25 to 55% of thecombined cross sectional areas of the remote passages is satisfactory.Preferably, the arrangement is such that the adjacent passages are about40% of the area of the remote passages in accordance with the exampledescribed above.

After the cooling liquid has passed through the chamber 7 in thecylinder head it is carried oif through outlet 20 and flows in a conduit2| to the radiator previously mentioned through which the cooling liquidcirculates before being returned to the engine block inlet ll. In thepresent instance the outlet 28 is disposed at a central portion of thecylinder head so that the cooling liquid flows through the chamber 1from the ends of the cylinder head toward the central portion thereof.

uid passages which supply coolant to the chamberv l in the head from thejacket in the engine block. The ratio between the aggregatecrosssectional areas of the remote passages to the aggregatecross-sectional areas of the adjacent passages varies inversely with thedistance between the inlet ll into the cooling jacket 55 of the engineblock and the outlet from the cooling chamber 1 of the cylinder head. Ifthe outlet 2i) were to be moved to the right, as viewed in Figs.

. l and 2, so that it approaches the end of the engine at which theinlet i1 is disposed, then the relative areas of the adjacent passagesL, M, N, P, R, S, and T would be decreased while the relative areas ofthe remote passages A, B, C, D,

E, F, and G would be increased. Conversely, if

the outlet 29 were moved to the left the adjacent passages would beincreased in cross-sectional area while the remote passages would bedecreased in relative cross-sectional area.

In differentiating between remote and adjacent cooling liquid passagesinto the cylinder head chamber 1 the central inlets H, J, K have beendisregarded. This is for the reason that the cooling liquid entering thechamber through these inlets has a minimum flow in contact with the hotsurfaces of the bottom compression wall I of the cylinder head. Inconstructions such as illustrated, where the inlet ll is located at oneend of the engine blockthe inlet passages such as H, J and K, which arelocated near the outlet flow through the engine jacket l5 adjacent theinlets H, J and K. Accordingly, if these central passages are ofexcessive cross-sectional area they bleed off cooling liquid at thispoint in its travel so that it does not travel the full length of thejacket i5 and up into the cylinder head through the remote passages.Preferably the central inlets H, J and K are of relatively small size;less than the total cross-sectional area of the adjacent passages.

Although the regulation of the available crosssectional areas of thecooling liquid passages I. communicating between the chamber 1 in the.

cylinder head and the cooling liquid jacket 15 in the engine block havebeen described With'their cross-sectional areas controlled by the sizevof the opening through the bottom compressionwall I of the cylinderhead, substantially the same results may be accomplished by adjustingthesizes of the openings through the gasket I6 or through the top wallof the engine block 3,

Over portions of the bottom compression wall l forming the domes 4 ofthe combustion chambers 5 it is desirable to have a relatively highvelocity flow of cooling liquid for a scouring ac tion which entrainsand scavenges therefrom any,

Fig. 4 shows the choke areas through spark plug boss 23 at one end ofthe cylinder head, and the" choke section illustrated in Fig. 6corresponds to that through the spark plug boss (see Fig.1). Each of thechoke sections has an available crosssectional area of combinedpassageways for the flow of cooling liquid which is greater than thecombined cross-sectional area of the passages from the jacket 15 whichfurnished the coolingliquid to flow through that particular chokesection. For example, the choke section through spark plug boss 22 has atotal area available for the flow of cooling liquid greater than thecom,

bined cross-sectional areas of the passages A, B, and C, and the chokesection through spark plug boss 2% has an available area for the flow ofcooling liquid greater than the'combined cross-sectional areas of thepassages A, 13,0, D, E, F, and

G. Thus, while it is desirable that the choke sec-1.

tions have restricted passages for the flow'therethrough of the coolingliquid, they do not impede the flow suificiently .so that the coolingliquid backs up and interferes with the free entrance of fresh coolingliquid through the passages leading from the jacket 55 in the engineblock.

In order that there is no backing up of the cooling liquid from theoutlet 20, the latter is preferably substantially equal incross-sectional area available for the flow of cooling liquid to thelargest choke section over the combustion chambers. Because of thedifference in frictional effeet between a single large circular passageand a plurality of odd shaped passages of equal total area, it issatisfactory if the outlet 20 be slightly less in cross-sectional areathan the total aggregate areas through the largest choke section. In thecylinder head illustrated, the outlet 20 has a cross-sectional areaabout 90% that of the total cross-sectional area of the passagewaysthrough the choke section illustrated in Fig. 6.

Since there are two choke areas corresponding to Fig. 6, the availablearea of the outlet 20 is 1 about 45% of the total passageway areathrough the next adjacent choke sections flowing cooling liquid thereto.

The individual passageways comprising the I .engineblock,- shows that.individual passageway areas through each of the choke sections, sothatthe greatest passage is not substantially morev than three times thearea or the smallest of that particular choke, assures a relatively highvelocity of flow over the entire choke area, providing an eflicientscavenging of steam therefromand an. effective cooling of the combustionchamber wall.

'Fig. 5, Which is a transverse section through the. posts 9, which holdthe cylinder head to the a, relative equality or uniformity in thecross-sectional areas of the various passages available for the flow ofcooling liquid through the cylinder head is maintained. In order thatthe proper relationship may be maintained between the variouspassageways.

through the choke sections, ribs 21 are formed on the under side of theupper wall 6 of the;

cylinder head. These ribs depend into the cooling liquid chamber 1 atthe choke section and reduce the effective area of the passagewaysl and94. This decrease in area of these passageways increases the resistanceto the flow therethrough of cooling liquid, so that, in the case of thechoke section illustrated in Fig. i, a greater relative proportion ofthe cooling liquid flows through the passageways ll, 12 and it, and inthe choke section illustrated in Fig. 6 a greater proportion of thecooling liquid flows through the passageways 9!, S2 and 93.

In carrying out the present invention there are various controllingfactors which may be regulated to obtain the desired cooling of thecylinder head of any'particular internal combustion engine. In the eventthat the position of the inlet ll, leading to the cooling liquid jacketl of the engine block, and the outlet passage 25, through which coolingliquid flows away from the cylinder head; are fixed by the design of theengine, the cooling characteristics of the system may be satisfactorilyregulated by adjustment of the cross-sectional areas of the coolingliquid passages which'control the flow of cooling liquid from thechamber Q55 in the engine block to the chamber I in the cylinder headand the relative cross-sectional areas of each'of the passagewaysthrough the several. choke sections. For example, if one portion of thecylinder head normally operates at a temperature which is considered toolow, one or more of the cooling liquid passages which supply coolingliquid to that portion have their cross-sectional areas reduced so thatan increased resistance is offered to the flow of cooling liquid intothat portion of the'cylinder head. -This results in cooling liquidhaving a decreased heat capacity, flowing over that portion of thecylinder head and diminished cooling results. Also a rib such as the rib2? may be formed in the chamber I-depending from the top wall -6 andtransverse to the general direction of flow through the cylinder head.Thisrib increases the resistance to the flow of cooling liquid to thatportion of the cylinder head and It temperature occurs on both sides ofthe rib in asmuch as the rate of flow is generally decreased so thatthere is a backing, up on one side or" the rib and a failure to feedcooling liquid to the apposite side of v the rib.

through the chamber 'a' chambers has its upper walls maintained atsubstantially the same temperature as every other like wall of acombustion chamber. In this manner uniform operating conditions areobtained for all of the cylinders in the engine block which results inan improved burning of the fuel charge in each of the combustionchambers. Since all the combustion chambers are maintained atsubstantially the same temperature and the charges of fuel introducedinto the chambers are substantially alike and uniform incompositiOn asmooth running engine is obtained which gives a substantially constantand uniform flow of power.

The cooling liquid flowing through the-cham- .ber l in the cylinder headproceeds in a gen eral direction toward the outlet 2!]. Aside from theposts 9 which receive the hold-down studs and the spark plug bosses, theonly obstruction to the flow of cooling liquid which extends are pillars28 which extend between theupper wall 6 and bottom wall l of thecylinder head beneath the ribs M and serve to strengthen the domes i.The pillars 28 and ribs Hi are more fully described in my 00-pending'application mentioned above. The cooling liquid flowing throughthe chamber 1 which is elevated to the highest temperature is that whichflows through the passages "'32 and 13,

[shown in the, choke section of Fig. 4, and the passages 92 and 93,shown in the choke section of Fig. 6,. particularly the passages 12 and92. This high temperature cooling liquid is not directed over succeedingdomes i overlying combustion chambers of the engine, but flows into thechannel. at one side of the head; that hot cooling liquid from passage12 flowing largely through the passageway 9| of the choke sectionillustrated in Fig. 6 and through a portion of the chamber ll removedfrom the domes over combustion chambers. coolant is obtained in Whichthat coolant raised to the highest temperature is not directed overportions of the compression wall I of the cylinder head which overliecombustion chambers of the engine. Thus there is an avoidance ofcarrying of the high temperature coolant over relatively 'coolerportions of the cylinder head. Previous designs of cylinder heads haveendeavored to equalize'temperatures in various parts of the cylinderhead, by conducting the. fresh coolant first however, it is sought towithdraw the high temperature cooling liquid from the cylinder headcooling chamber as rapidly as possible and elevate the operatingtemperature of the portions of the combustion chamber formed by thebottom compression wall I of the cylinder head near the passageways 13vand M and 93 and 94 by choking the cross-sectional area of such passage-Accordingly, a flow of the ways to retard the flow therethrough of thecooling liquid. Thus there is a quantity of cooling liquid of diminishedheat capacity flowing over these portions of the combustion chamber andless heat is withdrawn and the average temperature of adjacent portionsof the cylinder head and combustion chamber is raised. In addition "torestricting the flow of cooling liquid by diminishing thecross-sectional area of the passageways 13 and M and 93 and 94 a similarresult is accomplished by diminishing the relative cross-sectional areaof the inlet pasages such as the passages D, E, L, and M.

In describing the control of the cooling liquid flow through the chamber'1 attention has been directed to the regulation of the rate anddirection of flow by choke sections extending across the width of thehead. Such choke sectionsare also provided across the length of thecylinder head, as appears in Fig. 2, both ends of the head beingsubstantially symmetric about the transverse center line through theoutlet 20. In the case of cylinder heads having a center outlet, likethe embodiment illustrated, the control of the flow of cooling liquidtransversely across the width of the cylinder head cooling chamber be--comes of increased importance. However, the same principles described inconnection with the control of the longitudinal flow apply and need notbe repeated. Similarly, the relationship between the areas of thevarious inlets is regulated to obtain the desired rate and quantity offlow transversely across the cylinder head width. In this regulation theinlets A, D, H, L and R are the remote inlets, while the inlets C, F, G,K, N, P and T are the adjacent inlets, with respect to the cylinder headoutlet 29. The principles governing the control of the flow by inletsize are the same for the transverse flow as for the longitudinal flow.In the embodiment illustrated this feature of the invention is shown inFig. 3. Inlet or passage S adjacent the top side of the head, as viewedin that figure, is larger in area than the inlet or passage T adjacentthe bottom side of the head. Also inlet or passage H adjacent the topside of the head is of greater area than the inlet or passage K adjacentthe bottom side of the head. At the end of the cylinder head remote fromthe passages R and T the inlet or passage A adjacent the top side of thehead, as viewed in Fig. 3, is of greater cross sectional area than theinlet or passage C ad jacent the bottom side of the head. Each pair ofpassages mentioned are disposed substantially in line with one anotheracross the width of the cylinder head and, accordingly, passagesadjacent or along one side of the cylinder head may be said to begenerally of greater cross sectional area than the passages along oradjacent the other side of the head.

While this invention has been described in connection with an internalcombustion engine having an ignition device, it is to be understood thatit may be applied advantageously to engines of the semi-Diesel or Dieseltype. In a Diesel engine it is particularly desirable to have constant.temperature at each cylinder and a substantially uniform temperature atall cylinders, since the cylinder temperature influences. the time ofignition, which should occur reguvention has been illustrated, it is tobe understood that various alterations and substitutions in thearrangement of the various parts is contemplated and intended to bepracticed'in carrying out the principles of the invention as'describedabove.

What Iclaim is:

1. The method of cooling a multi-cylinder internal combustion engine,which comprises con- 5 tinuously flowing a liquid coolant over portions.

of the engine associated with the hot gases'of combustion in a generallyascending direction from an inlet in the engine block to an outlet inthe head, restricting the cross sectional area available for the flow ata plurality of successive stages in'the path from the engine block tialalinement, a cooling liquid chamber extending substantially the entirelength of the engine block in which the cylinders are formed, an inletfor receiving fresh cooling liquid, and means for forcing circulation ofthe cooling liquid, a cylinder head having top and bottom walls with acooling liquid chamber between the walls, aplurality of combustion faceson the under side of H the bottom wall, each overlying a combustionchamber of the engine associated with one of the cylinders, the headcooling liquid chamber being substantially continuous for the length ofthe engine block, a plurality of rows of post members extending throughsaid head chamber between the top and bottom walls, and integrallyformedv therewith, said rows disposed transversely across the width ofthe cylinder head to provide a series of cooling liquid compartments,each extending across the Width of the cooling liquid,

chamber, and the compartments being in intercommunication throughpassageways between posts of each row, said passageways in each rowhaving cross sectional areasproportioned to direct the flow of coolingliquid over the hottest portions of the bottom Wall in its coursethrough the head chamber. 7

3. In an aluminum cylinder head having ho regions overlying combustionchambers and regions overlying combustion facesf'of the cylinder head ofnormally greater extent and cooler than the hot regions, a chamber forthe circulation of cooling liquid, said chamber being continuous over aplurality of adjoining cylinders and having a plurality of liquid inletopenings adjacent each cylinder, a pluralityof members extending throughthe chamber and forming with the walls of the chamber a plurality 'ofpassages for the flow of cooling liquid through the chamber, some ofsaid memberspo'sitioned adjacent hot regions and having sockets for.ignition devices, a plurality of the passages lying in a cross sectionof the chamber through a hot regions and at right angles to the generalflow of cooling liquid, each of said plurality of passages having anarea proportioned to increase the flow of cooling liquid over the hotregion and decrease the flow over cooler regions, and the portion of thechamber overlying said cooler regions being relatively shallowtoincreasethe frictional resistance to flow of the cooling liquid oversuch shallowportions relative to the resistance to flow over the hot regions.

4. In a multi-cylinder internal combustion engine having a coolingliquid jacket in an engine block, a chambered cylinder head overlying aplurality of cylinders and having top and bottom walls, and means forcirculating a liquid coolant therethrough, the combination of a coolingliquid intake in the jacket of the block to receive freshcoolant,-acoolingliquidoutletinthe cylinder head, and inlet openingsinto the cylinder head chamber communicating with the cooling liquidjacket, said chamber overlying a plurality of combustion chambers andhaving a plurality of members extending therethrough between the top andbottom walls of the cylinder head, said bottom wall including aplurality of combustion faces,

each overlying a combustion chamber and having a hot region ofrelatively small area and a relatively cool region of greater area thanthe hot region, sockets in some of the members for receiving ignitiondevices, each said socketed member positioned at a hot region, meansassociated with the portions of the cooling chamber overlyingthe'relatively cool regions to restrict the relative flow of coolingliquid over such portions and increase the relative flow of coolingliquid over the hot region, said means comprising a top wall of thechamber positioned in relatively close proximity to the bottom wall ofthe chamber to provide a relatively shallow liquid passage having anincreased frictional resistance to the flow of liquid coolant there-,through, inlet openings of relatively small area for admitting liquidcoolant to the chamber to flow over cool regions and of relatively largearea for admitting liquid coolant to the chamber to flow over hotregions, and the inlet remote from adjacent thereto. 7

5. The method of cooling a multi-cylinder internal combustion engine,which comprises continuously flowing a liquid coolant over portions ofthe engine associated with the hot gases of combustion in a generallyascending direction from an inlet in the engine block to an outlet inthe head, restricting the cross sectional area available for the flow ata plurality ofv successive stages in the path from the engine blockinlet to the head outlet, regulating the cross sectional area of theseveral passageways at'each restricted stage with respectto one anotherto ob-- tain a controlled velocity of flow through all of saidpassageways, and confining the'cooling liquid between successive stagesto regions under the influence of flow velocity from the precedingrestricted stage, whereby all the cooling liquid is moved by the flowvelocity developed at the restricted stages to eliminate pools ofnon-flowing cooling liquid.

6. The method of cooling, a multi-cylinder internal combustion engine,which comprises continuously flowing a liquid coolant over portions ofthe engine associated with the hotgases of combustion in a generallyascending direction from an inlet in the engine block to an outlet inthe head, restricting the cross sectional area available for the flow ata plurality of successive stages in the path from the engine block inletto the head outlet, regulating the cross sectional area of the severalpassageways at each restricted stage with respect to one another toobtain a controlled velocity of flow through all of said passageways,regulating the relative total cross sectional area at each restrictedstage to obtain a controlled flow of cooling liquid through allsuccessive stages, and confining the cooling liquid between successivestages to regions under the influence of flow velocity from thepreceding restricted stage, whereby all the cooling liquid is i moved bythe flow of velocity developed at the restricted stages to eliminatepools of non-flowing cooling liquid.

7. The method of cooling a multi-cylinder internal combustion enginehaving a jacketed cylinder block'and a chambered cylinder head for theflow therethrough of a cooling liquid, with different portions of thehead chamber overlying the several combustion chambers of the engine,which comprises continuously introducing cooling liquid into the jacketin the block, flowing the cooling liquid through the jacket in theblock, simultaneously conducting the cooling liquid from the blockjacket into the chamber in the head through a plurality of groups ofindividual courses, flowing the cooling liquid from all of theindividual courses in the general direction of an outlet from the headchamber and in heat exchanging relation with portions of thecylinderhead to be cooled, all of the cooling liquid flowing into thehead chamber through all of said individual courses being movedsubstantially continuously solely in the general direction of the outletsubstantially from the time it enters the cooling liquid chamber untilit reaches the outlet, commingling the cooling liquid in the headchamber from a first group of the individual courses, simultaneouslyflowing different portions of the comrningled cooling liquid in thegeneral direction of the outlet from the head chamber and over aplurality of separate courses tities of cooling liquid flowing thereoverto be proportional to the quantities of heat to be removed from theportions of the cylinder head adjacent each of the courses, comminglingthe cooling liquid from the several courses of said first controlsection with cooling liquid introduced into the head chamber through asecond group of the individual courses from the block jacket,simultaneously flowing different portions of the last named commingledcooling liquid in the general direction of the head outlet and over aplurality of separate courses comprising a second control section in thehead chamber spaced from said first control section in the generaldirection of the head outlet, proportioning the relative cross-sectionalareas of the separate mingled cooling liquid in the general direction ofthe outlet and over portions of the cylinder head to be cooled, andconducting the last named commingled cooling liquid out of the headchamber.

8. In a multi-cylinder internal combustion en- 1 gine, an engine blockhaving sides and ends and a plurality of cylinders disposed insubstantially side by side relation, a'cooling liquid jacket in theblock in heat exchanging relation with the cylinders, a cylinder headoverlying the cylinders and having ends and sides disposed adjacent theends and sides respectively of the block, a

cooling liquid chamber formed in the head and extending longitudinallyof the engine and across the ends of the cylinders, an intake at one endof the block for admitting coolant to the jacket;

an outlet at one side of the head for discharging liquid from thechamber, a multiplicity of disuj tributed passages between the jacketand chamremote from the inlet being generally of greater cross sectionalarea than the passages adjacent the inlet, and the passages adjacent oneside of the head being generally of greater cross sec- EVERETT G.FAHLMAN.

her, the passages adjacent the end of the jacket

